Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5813_Библиотеки_им_академика_М_И_Перельмана.pdf
216
C. Giussani et al.
During the time lapse between the radiology
department and the operating room posttraumatic intracranial hematomas and brain contusions might develop or increase in size. Such
evolution might obviously affect patients’ prognosis and outcome but it also affects the management of the patient during surgery that may be
performed blindly, especially in case of development of contralateral hematomas or in case of
growing hematomas [9]. Furthermore this same
scenario can occur intraoperatively, when the
opening of a close system such as the skull is
modied, leading to changes in blood inow and
outow and CSF dynamics, ultimately changing
brain perfusion and intracranial pressure.
In such an emergency setting, a real-time
intraoperative imaging modality can be of help in
evaluating a lesion under development, allowing
a real-time scanning of the surgical eld.
Intraoperative imaging techniques available in
neurosurgery are computed tomography (CT)
scan, magnetic resonance imaging (MRI), and
ultrasound (US). The rst two techniques are
very accurate but they are cost and time consuming and they could not be useful in an emergency
setting especially for the amount of time needed
to achieve a full brain scan [10]. Intraoperative
US (ioUS) is less expensive than the rst two
techniques and it does not require radiology technicians or dedicated personnel, nor involve the
use of ionizing radiations. Such characteristics
make ioUS available in many neurosurgical centers and 24/7 [10, 11].
In current neurosurgical settings, ioUS is
mainly used in B-mode to perform a morphological evaluation of the surgical eld, in order to
localize supercial and deep-seated lesions after
bone ap removal; fusion imaging with preoperative imaging allows orientation and comparison
with other imaging modalities [12, 13].
Ultrasound is nowadays a multiparametric imaging modality with advanced functions [14]:
• Color Doppler scans in order to locate vessels
and understand their integrity after surgery
[15, 16]
• Sonoelastograms that are able to assess
mechanical properties of brain tissues [17–19]
• Contrast-enhanced scans that are able to
describe pathological brain tissue and to perform perfusion studies able to understand the
areas of secondary damage [20–22]
For its versatility, the use of ioUS is becoming
more widespread and it is now a fundamental
tool in the neurosurgical equipment [11]. In fact,
intraoperative real-time imaging has demonstrated to have several advantages over preoperative imaging since anatomy can change during
surgery due to brain shifting and physiopathological and surgically induced tissue deformation
[23]. Despite the extensive literature reporting
the cost-effective benets of ioUS and the
increased quality of imaging through the years,
neurosurgeons do not generally consider ioUS as
a user-friendly technique [24]. This is mainly
related with the fact that ioUS is not used a standard diagnostic tool, the topographic anatomy is
not clear, and it employs scans that differ from
the three standard preoperative orthogonal planes
since pictures are mainly acquired in 2D along
several variable planes different from the three
standard ones. These problems can be overcome
by an appropriate training which requires daily
elective practice to better understand probe and
image orientations, to increase the ability to
interpret anatomy and to reduce the time spent to
understand the pictures acquired [24].
Nowadays, ioUS is mainly used for neuro-
oncological, epilepsy, and vascular neurosurgery.
In the neuro-oncological and epilepsy setting,
ioUS is used to localize the lesion, to check for
complete resection at the end of surgery, and to
correct the neuro-navigation according to the
brain shift during the surgical removal of the
tumor [12, 13, 15, 20, 21, 25, 26]. Contrastenhanced US (CEUS) is used for better denition
of a lesion and to better dene the perilesional
tissue, while color Doppler technique might be
useful in some cases with major vessel
encasement. Moreover, some advanced reports
deal with the utility of sonoelastogram in understanding the mechanical properties of the brain
and differentiating between low-grade and highgrade gliomas [17, 19, 20]. For what concerns
vascular neurosurgical cases, ioUS is mainly
19 Intraoperative Echo inTBI
217
used for arteriovascular malformation (AVM)
localization and color Doppler or angiosonographic studies of AVMs or dural arteriovenous
stulas in order to dene the intraoperative occlusion of the malformation after surgery [15, 16,
27, 28].
Moreover, in some cases, ioUS is used for
external ventricular drain (EVD) placement [29],
especially when free-hand technique is at high
risk of malpositioning, and drainage of cystic
lesions like brain abscesses [30].
In case of TBIs, ioUS is not routinely used in
neurosurgical procedure and, despite its realtime capacities, has not been employed to
understand during surgery the evolution of the
dramatically dynamic phenomena that occurs in
trauma patients. Also ioUS does not have nowadays a denitive role in dening the prognosis
and outcome of patients undergoing surgery for
major brain injuries. As a consequence only few
series of patients or case reports have been
reported in the literature regarding the utility of
ioUS; most of them deal with decompressive
craniectomy (DC) for ICP control after failure
of medical management [31, 32]. Besides these,
some experimental models have been described
in order to understand the potential utility of
ioUS [33].
In this chapter we are going to describe the
multiple options that ioUS can offer in the surgery of major TBIs in an emergency setting.
19.2 Utility ofioUS inTBI
Performing surgery in patients with traumatic
brain lesions is like interfering on the natural history of a major TBI without having control on it.
As a consequence, during the time lapse between
the diagnostic CT scan and the postoperative CT
scan, each patient can develop post-traumatic
lesions other than the one for which surgery is
being done.
Routine use of ioUS may be of help in order to
control during surgery if a patient is developing
other post-traumatic lesions such as posterior
fossa hematomas or homolateral and contralateral hematomas since ioUS allows to explore
contralateral hemisphere and posterior fossa
structures.
Moreover, an intraoperative picture of brain
parenchyma may be of help in order to understand the persistence of brain shift or uncus herniation after a decompressive craniectomy (DC).
Finally, evaluating the dimensions of ventricles
in some cases may lead to a direct placement of
an EVD under US guidance which can reduce the
risk of malpositioning.
Furthermore, advanced ioUS modalities such
as CEUS and SEG might be helpful in understanding vessel integrity and tissue perfusion,
highlighting contusions, and showing parenchymal edema/elasticity.
19.2.1 Intraoperative Use ofUS
In an emergency setting it is difcult to routinely
use ioUS since surgery needs quick decisionmaking and a fast performance. As a matter of
facts, reports about ioUS use in TBIs mainly
regard case reports or small case series of patients
undergoing DC after failure of medical
management.
In this small burden of papers, of some note is
the study by Hepner and colleagues that report
the use of CEUS in patients undergoing DC for
ICP control [31]. In their work, they report the
results of cerebral perfusion measured with
CEUS in a series of six patients undergoing
DC.In particular, it has been shown that cerebral
perfusion can increase after DC and that CEUS
during ioUS can be used as a reference for postcraniectomy check of the brain perfusion at the
bedside of the patient during the stay in
ICU. Patients without the bone ap can be
explored with US with or without CEUS and in
some cases secondary damage can be seen like
areas of hypoperfusion due to uncontrolled ICP
[31, 34].
Another interesting study is the one by He and
colleagues [32]. In their study they showed the
potential utility of CEUS in patients undergoing
resection of contused brain showing how CEUS
was able to identify more hypo-perfused brain
tissue than the standard US.
218
C. Giussani et al.
Other few experiences are available in literature but they deal with experiences of small
groups of patients or of case reports [7]. This is
mainly related with the fact that there is still not a
routine use of ioUS in TBIs during surgical procedures and this might be due to:
• Difcult management of a new imaging tech-
nique in an emergency setting
• No known benets about the usefulness of
routinary use of ioUS in patients with TBIs
19.2.2 Possible Scenarios
As reported above, surgery for TBI can present
some obstacles that requires some changes from
what was briey planned preoperatively. In particular, patients can present unexpected bleedings
due to a damage of major vessels, hematomas in
the contralateral hemisphere, and further evolution of hidden contusions after release of the
intracranial pressure.
Contralateral hematomas can be considered a
common complication of major TBIs but they
do not generally require surgical intervention.
In fact, bilateral small contusions can be considered a common nding such as evolution of
small subdural hematomas without signicant
mass effect. In fact, surgical management of
contralateral site hemorrhages is considered a
rare event and about 50 case series are reported
in literature [6–9]. Such hematomas especially
occur after evacuation of acute subdural hematomas (ASDH). In quite all cases such event
occurs immediately during surgery and it
requires a quick planning of a new surgical procedure. Only a couple of case reports dealt with
the fast management of such complications
using ioUS. The most interesting and well
described is the one from Pil Soo Kim etal. [7]:
in their experience, the use of ioUS determined
a fast shifting from a unilateral surgery to a
bilateral surgery that allowed to minimize the
secondary damage due to a fast-growing contralateral hematoma. According to their experience, ioUS can allow to check for complications
after surgery in TBIs while the patient is still in
the operating room. This is in line with our
experience as reported in the explanatory cases
of this chapter.
Another clinical scenario can involve patients
with post-traumatic hematomas managed conservatively. In fact, sometimes post-traumatic hematomas can be managed conservatively in the rst
instance but some of them require a delayed surgical evacuation due to increase of perilesional
edema. In these cases, colliquation of blood
allows endoscopic evacuation of the clot that can
be guided by ioUS.In fact ioUS can be used for
localizing the clot and for checking the volume of
hematoma after evacuation. In other cases, hematomas can be liquid enough in order to be drained
under US guidance [35].
Finally, in case of brain swelling due to TBIs
it might be necessary at the end of a DC to place
an EVD.In these cases, EVD placement can be
considered challenging even for experienced
neurosurgeons since usually ventricles are collapsed due to the brain edema. In such a scenario,
the presence of a large bone defect is of help in
order to use the US probe and place an EVD
under US guidance [29].
19.2.3 Explanatory Cases
19.2.3.1 Case n. 1
Seventy-six-year-old lady presenting to the A&E
department intubated on the scene after a brain
injury with left-sided anisocoria and GCS 3 due
to sedation. The CT scan at presentation (see
Fig. 19.1) documented the presence of a leftsided ASDH with a rounded isodense lesion in
the right frontal lobe without any mass effect.
Due to the clinical presentation and the radiological focal hematoma, it was decided to perform a
left-sided craniotomy for evacuation of the
ASDH.During surgery, a sudden brain swelling
was experienced after clot evacuation. For this
reason, a B-mode ioUS scan was performed that
documented a right-sided post-traumatic frontal
hematoma with mass effect and a midline shift
(see Fig.19.1). Due to the documented formation
of the hematoma, it was decided to perform a
right-sided frontal craniotomy. At the opening of
cd
19 Intraoperative Echo inTBI
ab
219
Fig. 19.1 Explanatory case n. 1. (a) Preoperative brain
CT scan showing a right-sided frontal rounded contusion
and a left-sided extradural hematoma. (b) Intraoperative
US after left-sided craniotomy showing a big right frontal
the dura, a large right frontal hematoma was
found. Postoperative CT scan of the brain documented the surgical cavity and clot removal.
contusion with midline shift and intraventricular clot (RF
right frontal lobe; *left ventricle). (c) Postoperative CT
scan. (d) Intraoperative US after removal of the right frontal hematoma
ment where he started having intractable seizure.
He was intubated by the emergency team and he
underwent an antiepileptic treatment and a subsequent fast brain MRI that showed a large frontal
19.2.3.2 Case n. 2
A 10-month-old baby boy fell from the changing
table having a traumatic head injury from a 1.3m
height. He was transported to the A&E depart-
contusion without signicant mass effect (see
Fig.19.2a). The EEG showed a persistent seizure
after suspension of sedation despite anticonvulsive therapy. Given this nding we decided to
220
ab
cd
C. Giussani et al.
Fig. 19.2 Explanatory case n. 2. (a) Preoperative brain
MRI showing a right frontal hematoma. (b) Postoperative
brain MRI showing the surgical cavity in the frontal lobe.
evacuate the hematoma with a small frontal craniotomy and a minimally invasive procedure
through a small corticectomy. IoUS was performed and it was helpful to quantify the amount
of blood before opening the dura mater
(Fig. 19.2c) and after clot removal in order to
understand if there were any blood remnants (see
Fig.19.2d). Postoperative scans showed removal
of the clot without complications in the surgical
cavity (see Fig.19.2b).
(c) Intraoperative US showing the right frontal lobe hematoma. (d) Intraoperative US showing the surgical cavity
After surgery the baby slowly resolved the
grand mal seizures and recovered in a couple of
weeks returning back to home.
This case is of interest because of its rarity and
because it brings light on the potential use of US
in the emergency setting in case of pediatric
TBIs. In fact, in some cases involving newborns
and infants with open anterior fontanel, US can
be performed at the bedside and it is particularly
important in case of unstable conditions that do
19 Intraoperative Echo inTBI
221
not allow transfer to the radiology department. In
these cases, US through the bregmatic fontanel
can be used to briey exclude signicant lesions
with mass effect or midline shift or it can be used
to observe the evolution of TBIs. In case of minor
injuries, it can also be used to avoid a brain CT
scan and to reduce the exposure to ionizing
radiations.
19.3 Future Perspectives
Routine use of ioUS allows to open further perspectives in prognosis stratication of patients
with major TBIs. In fact, ioUS can be performed
as a baseline evaluation of the brain at the moment
of surgery that can be used for future comparisons during the ICU recovery [31]. Moreover, it
can be used as a way to estimate the primary and
secondary brain damage at the beginning of the
clinical history of a patient [32]. As a matter of
fact, the majority of the published studies deal
with the role of US in patients who have undergone DC [31, 32, 34, 36]. The presence of a large
bone defect determines the possibility to explore
the brain with the US probe without the interference of the skull that, in many cases, makes the
brain inaccessible to the US.
One of the issues in comparing the preoperative and postoperative ndings is the region of
interest to be used in order to appreciate US
changes in terms of perfusion or brain elasticity.
As proposed by Hepner etal. in 2006, comparison of brain perfusion with CEUS can be performed using the rst burr hole performed for the
DC as “the region of interest” (ROI) for further
postoperative comparisons [31]. Moreover, they
were able to perform the preoperative scans with
a small burr hole probe. In their study acquisition
of perfusion data was performed only on six
patients but they assessed that DC was related
with an improvement of brain perfusion at the
postoperative US scans. With this perspective,
future studies may be directed to distinguish
between patients with low response to DC and
patients with a good response to DC.
In a study by He and colleagues the utility of
ioUS with CEUS in traumatic brain injuries was
reported on a series of 32 patients [32]. In one
group they performed standard ioUS while in the
other group they performed ioUS with
CEUS.They showed interesting results about the
information that CEUS can add to the normal
US.In fact, according to their study, CEUS can
show the difference between vital brain and
hypo-perfused dead-brain tissue that can appear
normal at the standard US.Findings about vital
or dead brain can change the surgical plan in case
of resection of brain contusion or in case of surgery of intraparenchymal hematomas. As a matter of fact, in the study by He etal. it was found
that CEUS demonstrated a larger hypo-perfused
brain area around the contused brain tissue than
was planned to be removed. In those cases of
brain with low perfusion at CEUS, neurosurgeons planned a larger brain resection. Despite
their interesting ndings, their study had some
limitations such as the lack of a longitudinal follow- up in order to understand if removal of perilesional damaged brain can increase patient’s
outcome reducing the secondary brain damage
due to cytotoxic edema, or the simple resection of
the contused area could lead to a recovery of the
perilesional area.
Moreover, starting from this point, brain stiffness at the time of DC may be studied with the
systematic performance of elastosonography
with ioUS. In fact, one of the new frontiers in
brain US is the study of brain elastance. Elastance
can be measured applying the US probe on the
brain surface and it can give information about
pathological conditions of the brain, like it has
been described in experimental models of ischemic strokes in mice or in case of patients with
brain tumors [17, 37].
Moreover, changes of stiffness may reect
changes of brain perfusion. In a previous work by
Xu and colleagues it was found that in a rodent
model of ischemic stroke there were changes in
brain elastograms due to reduction of brain perfusion and increase of brain edema [38]. The
same research group studied a rodent model of
TBI [33]. In their study, they found that US elastography is able to detect changes in the uid
content of the brain after a mild brain trauma. In
a speculative way, given these reports and the
222
C. Giussani et al.
raising knowledge about MR elastography, it will
be possible to prognosticate the outcome of a
patient with high ICP and with repeated measures of brain elastance with brain US.Moreover,
comparison with intraoperative ndings will possibly allow to distinguish patients with poor
prognosis from patients with a good outcome.
References
1. Carney N, Totten AM, O’Reilly C, etal. Guidelines
for the management of severe traumatic brain injury,
fourth edition. Neurosurgery. 2016;80(1):6.
2. Management of Concussion/mTBI Working Group.
VA/DoD clinical practice guideline for management
of concussion/mild traumatic brain injury. J Rehabil
Res Dev. 2009;46:CP1–68.
3. Vella MA, Crandall ML, Patel MB. Acute management of traumatic brain injury. Surg Clin North Am.
2017;97:1015–30.
4. Murray GD, Brennan PM, Teasdale GM.Simplifying
the use of prognostic information in traumatic brain
injury. Part 2: graphical presentation of probabilities.
J Neurosurg. 2018;128:1621–34.
5. Brennan PM, Murray GD, Teasdale GM.Simplifying
the use of prognostic information in traumatic brain
injury. Part 1: the GCS-pupils score: an extended index
of clinical severity. J Neurosurg. 2018;128:1612–20.
6. Shen J, Pan JW, Fan ZX, Zhou YQ, Chen Z, Zhan
RY. Surgery for contralateral acute epidural hematoma following acute subdural hematoma evacuation: ve new cases and a short literature review. Acta
Neurochir. 2013;155:335–41.
7. Kim PS, Yu SH, Lee JH, Choi HJ, Kim
BC. Intraoperative transcranial sonography for
detection of contralateral hematoma volume change
in patients with traumatic brain injury. Korean J
Neurotrauma. 2017;13:137.
8. Su T-M, Lee T-H, Chen W-F, Lee T-C, Cheng
C-H. Contralateral acute epidural hematoma after
decompressive surgery of acute subdural hematoma: clinical features and outcome. J Trauma.
2008;65:1298–302.
9. Choi YH, Lim TK, Lee SG. Clinical features and
outcomes of bilateral decompression surgery for
immediate contralateral hematoma after craniectomy following acute subdural hematoma. Korean J
Neurotrauma. 2017;13:108.
10. Moiyadi A, Shetty P. Objective assessment of utility of intraoperative ultrasound in resection of central nervous system tumors: a cost-effective tool for
intraoperative navigation in neurosurgery. J Neurosci
Rural Pract. 2011;02:004–11.
11. Pino M, Imperato A, Musca I, etal. New hope in brain
glioma surgery: the role of intraoperative ultrasound.
A Review. Brain Sci. 2018;8:202.
12. Velthoven V.Intraoperative ultrasound imaging: comparison of pathomorphological ndings in US versus
CT, MRI and intraoperative ndings. In: Bernays RL,
Imhof H-G, Yonekawa Y, editors. Intraoperative imaging neurosurgery. Vienna: Springer Vienna; 2003.
p.95–9.
13. Sun H, Zhao JZ. Application of intraoperative ultrasound in neurological surgery. Minim Invasive
Neurosurg. 2007;50:155–9.
14. Mannaerts CK, Wildeboer RR, Postema AW,
Hagemann J, Budäus L, Tilki D, Mischi M, Wijkstra
H, Salomon G. Multiparametric ultrasound: evaluation of greyscale, shear wave elastography and
contrast-enhanced ultrasound for prostate cancer
detection and localization in correlation to radical
prostatectomy specimens. BMC Urol. 2018;18:98.
15. Prada F, Del Bene M, Faragò G, DiMeco F. Spinal
dural arteriovenous stula: is there a role for intraoperative contrast-enhanced ultrasound? World
Neurosurg. 2017;100:712.e15–8.
16. Bartels E. Evaluation of arteriovenous malformations (AVMs) with transcranial color-coded duplex
sonography: does the location of an AVM inuence its sonographic detection? J Ultrasound Med.
2005;24:1511–7.
17. Prada F, Del Bene M, Moiraghi A, etal. From grey
scale B-mode to elastosonography: multimodal
ultrasound imaging in meningioma surgery—pictorial essay and literature review. Biomed Res Int.
2015;2015:1–13.
18. Del Bene M, Perin A, Casali C, Legnani F, Saladino
A, Mattei L, Vetrano IG, Saini M, DiMeco F, Prada
F. Advanced ultrasound imaging in glioma surgery:
beyond gray-scale B-mode. Front Oncol. 2018;8:576.
19. Chauvet D, Imbault M, Capelle L, Demene C, Mossad
M, Karachi C, Boch A-L, Gennisson J-L, Tanter M.In
vivo measurement of brain tumor elasticity using
intraoperative shear wave elastography. Ultraschall
Med. 2016;37:584–90.
20. Prada F, Bene MD, Fornaro R, etal. Identication of
residual tumor with intraoperative contrast-enhanced
ultrasound during glioblastoma resection. Neurosurg
Focus. 2016;40:E7.
21. Mattei L, Prada F, Marchetti M, Gaviani P, DiMeco
F. Differentiating brain radionecrosis from tumour
recurrence: a role for contrast-enhanced ultrasound?
Acta Neurochir. 2017;159:2405–8.
22. Sastry R, Bi WL, Pieper S, Frisken S, Kapur T, Wells
W, Golby AJ.Applications of ultrasound in the resection of brain tumors: ultrasound in brain tumor resection. J Neuroimaging. 2017;27:5–15.
23. Reinertsen I, Lindseth F, Askeland C, Iversen DH,
Unsgård G.Intra-operative correction of brain-shift.
Acta Neurochir. 2014;156:1301–10.
24. Giussani C, Riva M, Djonov V, Beretta S, Prada F,
Sganzerla E. Brain ultrasound rehearsal before surgery: a pilot cadaver study: cerebral ultrasound in
cadaveric heads. Clin Anat. 2017;30:1017–23.
25. Coburger J, Scheuerle A, Pala A, Thal D, Wirtz CR,
König R. Histopathological insights on imaging
19 Intraoperative Echo inTBI
223
results of intraoperative magnetic resonance imaging, 5-aminolevulinic acid, and intraoperative
ultrasound in glioblastoma surgery. Neurosurgery.
2017;81:165–74.
26. Prada F, Gennari AG, Del Bene M, Bono BC, Quaia
E, D’Incerti L, Villani F, Didato G, Tringali G,
DiMeco F. Intraoperative ultrasonography (ioUS)
characteristics of focal cortical dysplasia (FCD) type
II b. Seizure. 2019;69:80–6.
27. Unsgård G, Rao V, Solheim O, Lindseth F.Clinical
experience with navigated 3D ultrasound angiography (power Doppler) in microsurgical treatment of
brain arteriovenous malformations. Acta Neurochir.
2016;158:875–83.
28. Prada F, Del Bene M, Saini M, Ferroli P, DiMeco
F.Intraoperative cerebral angiosonography with ultrasound contrast agents: how I do it. Acta Neurochir.
2015;157:1025–9.
29. Maneld JH, Yu KKH. Real-time ultrasound-guided
external ventricular drain placement: technical note.
Neurosurg Focus. 2017;43:E5.
30. Park H, Lee Y, Oh S, Lee HJ.Successful treatment
with ultrasound-guided aspiration of intractable
methicillin- resistant Staphylococcus aureus brain
abscess in an extremely low birth weight infant.
Pediatr Neurosurg. 2015;50:210–5.
31. Heppner P, Ellegala DB, Durieux M, Jane JA, Lindner
JR. Contrast ultrasonographic assessment of cerebral perfusion in patients undergoing decompressive
craniectomy for traumatic brain injury. J Neurosurg.
2006;104:738–45.
32. He W, Wang L-S, Li H-Z, Cheng L-G, Zhang M,
Wladyka CG. Intraoperative contrast-enhanced
ultrasound in traumatic brain surgery. Clin Imaging.
2013;37:983–8.
33. Xu ZS, Yao A, Chu SS, Paun MK, McClintic AM,
Murphy SP, Mourad PD.Detection of mild traumatic
brain injury in rodent models using shear wave elastography: preliminary studies. J Ultrasound Med.
2014;33:1763–71.
34. Sarà M, Sorpresi F, Guadagni F, Pistoia F. Realtime ultrasonography in craniectomized severely
brain injured patients. Ultrasound Med Biol.
2009;35:169–70.
35. Sadahiro H, Nomura S, Goto H, Sugimoto K, Inamura
A, Fujiyama Y, Yamane A, Oku T, Shinoyama M,
Suzuki M. Real-time ultrasound-guided endoscopic
surgery for putaminal hemorrhage. J Neurosurg.
2015;123:1151–5.
36. Bobinger T, Huttner HB, Schwab S.Bedside ultrasound after decompressive craniectomy: a new standard? Neurocrit Care. 2017;26:319–20.
37. Prada F, Del Bene M, Rampini A, etal. Intraoperative
strain elastosonography in brain tumor surgery. Oper
Neurosurg. 2019;17:227–36.
38. Xu ZS, Lee RJ, Chu SS, Yao A, Paun MK, Murphy
SP, Mourad PD. Evidence of changes in brain tissue stiffness after ischemic stroke derived from
ultrasound-based elastography. J Ultrasound Med.
2013;32:485–94.
Neurosonology inTropical
Medicine
DavidClark andPeterJohnAshtonHutchinson
Contents
20.1 Introduction 225
20.2 Neurosonology inNeurological Infections intheTropics 226
20.3 Human Immunodeciency Virus 226
20.4 Tuberculous Meningitis 227
20.4.1 Intracranial Hypertension inTBM 227
20.4.2 Tuberculous Meningitis- Related Vasculopathy 227
20.5 Cryptococcal Meningitis 228
20.5.1 Intracranial Hypertension inCrM 229
20.5.2 Vasculopathy inCrM 229
20.6 Neurocysticercosis 229
20.6.1 Intracranial Hypertension inNeurocysticercosis 230
20.6.2 Vasculopathy inNCC 230
20.7 Cerebral Malaria 230
20.7.1 Raised Intracranial Pressure inPaediatric CM 231
20.7.2 Transcranial Doppler inPaediatric CM 232
20.8 Neurosonology inNon- infectious Diseases inTropical Regions 234
20.8.1 Sickle Cell Anaemia 234
20.8.2 Hydrocephalus 234
20.8.3 Traumatic Brain Injury 234
20.9 Implementation ofNeurosonology inHealth Systems
inLow- andMiddle- Income Countries 235
References 236
20
D. Clark (*) · P. J. A. Hutchinson
National Institute of Health Research Global Health
Research Group on Neurotrauma, Cambridge
University Hospitals and University of Cambridge,
Cambridge, UK
Division of Neurosurgery, Addenbrooke’s Hospital,
Cambridge, UK
e-mail: dj.clark@cantab.net; pjah2@cam.ac.uk
© Springer Nature Switzerland AG 2021
C. Robba, G. Citerio (eds.), Echography and Doppler of the Brain,
https://doi.org/10.1007/978-3-030-48202-2_20
20.1 Introduction
‘Tropical medicine’ refers to the eld of medicine
that deals with pathologies, both infectious and
non-infectious, that are prevalent in tropical and
subtropical regions. Many of the diseases in this
225
226
D. Clark and P. J. A. Hutchinson
region result from poverty, poor sanitation, infrastructure and inadequate health sources [1].
Although infectious diseases have historically
been the greatest challenge to healthcare providers in these regions, ageing populations and rapid
urbanisation mean non-communicable diseases
(such as trauma and cerebrovascular disease) are
becoming increasingly prevalent in low- and middle-income countries (LMICs). Neurosonological
techniques are a relatively inexpensive, non-invasive method of obtaining detailed information on
intracranial pressure and haemodynamics. As
such, neurosonology represents an exciting
opportunity to better understand and improve the
management of neurological conditions prevalent
in the tropics where advanced diagnostic modalities such as neuroimaging or invasive multimodality neuromonitoring are not routinely available.
In this chapter, we aim to review the literature on
the role of neurosonology in a number of neurological diseases typically encountered by doctors
and other healthcare professionals working in
tropical medicine and propose that it remains an
underutilised technique in this environment. In
addition, recommendations are made to help
ensure effective and responsible implementation
of neurosonology for those wishing to adopt it
into their own tropical medicine practice.
20.2 Neurosonology
inNeurological Infections
intheTropics
Neurosonology in tropical neurological infections has two main applications—transcranial
Doppler ultrasound (TCD) and ultrasound optic
nerve sheath diameter (ONSD) as non-invasive
methods to diagnose raised intracranial pressure
(ICP) in low-resource settings where invasive
methods are unavailable or impractical, and TCD
to evaluate vasculopathy secondary to infection.
In the sections that follow, we present a brief
overview of the epidemiology, clinical features,
diagnosis and treatment of each condition followed by a review of perturbations in intracranial
haemodynamics associated with each pathology
and, nally, the role of neurosonology in their
clinical management. We have decided to focus
on ve neurological infections that are prevalent
in many tropical and subtropical countries—HIV,
tuberculous meningitis, cryptococcal meningitis,
neurocysticercosis and cerebral malaria. The role
of neurosonology in central nervous system
infections that are also prevalent in temperate
regions (such as meningoencephalitides, brain
abscesses and subdural empyema due to various
aetiologies) is not covered here as this is discussed in greater detail elsewhere.
20.3 Human Immunodeciency
Virus
The incidence of stroke in LMICs is increasing,
especially in young populations [2]. HIV infection is an important risk factor for stroke in
endemic regions [3]. HIV-associated vasculopathy is an important cause of HIV-related ischaemic stroke [4, 5] and can be dened as intimal
hyperplasia more than expected for age in an
HIV patient, which includes several pathological
ndings including accelerated atherosclerosis,
non-atherosclerotic vasculopathy, vasculitis and
small-vessel disease [6].
Two authors have published their experience
of the use of TCD examination to assess vasculopathy in HIV infection [7, 8]. Brilla etal. found
that both mean blood ow velocities of the MCAs
were reduced and cerebral vasoreactivity
(assessed using increase in mean blood ow
velocity after administration of intravenous acetazolamide) was impaired in HIV-infected individuals (n = 31) relative to healthy controls
(n = 10) [7]. Similarly, Chow et al. found that
cerebral vasoreactivity (assessed using the
response of cerebral blood ow to inhaled carbon
dioxide) was impaired in 65 antiretroviral
therapy- treated, virally suppressed HIV-infected
individuals relative to 28 healthy controls [8].
The exact signicance of these ndings remains
unclear but points to the possibility of intracranial endothelial dysfunction in response to
chronic HIV infection.
In addition to HIV-associated vasculopathy,
coagulopathy, cardiothromboembolism and,
importantly, opportunistic infections are
postulated to be important causes of HIV-related